ESD Susceptibility Analysis: Coupling to Traces and Interconnect

ESD susceptibility scanning is an effective method to find the causes of ESD soft failures in electronic systems. A local probe is used to scan the system for sensitive areas. However, the voltages induced by the probe are often unknown. This paper quantifies the induced voltages from different probes when injected into traces and flex cables, and compares the values to the induced voltages caused by an IEC 61000-4-2 ESD gun in contact mode. The goal is to guide the reader to select voltage levels and probes during susceptibility scans in a way that avoids levels that may be associated with ESD gun injection and cause failure.